This invention relates to a sweep circuit used in oscilloscopes and the like, and more particularly to an automatic sweep circuit for indicating a specific number of waveforms constantly on the screen of a cathode-ray tube by automatically making a sweep frequency follow the frequency of an input signal which may vary with time.
Generally, in prior-art sweep generators a sweep frequency suitable for the frequency of any input signal must be selected by manually changing a sweep range as required. It is difficult to observe such waveforms moving on the screen when the input signal frequency varies. There are various types of automatic sweep circuits now in use, which are however unsatisfactory in linearity of saw tooth waves or complicated in circuit design, and which are expensive if the linearity is improved.